Among the tissues of a human body, skin is directly exposed to an external environment and plays a role of a protective wall between the inside of a human body and an external environment. It provides a protection against external environment-contaminating substances including chemical substances, ultraviolet rays and invasion by microorganisms, and thus protects a living body from a surrounding environment. Skin color is determined by melanin, hemoglobin, carotene, or the like, and melanin plays the most important role among them. In addition to the determination of human skin color, melanin performs a skin protection function like ultraviolet absorption activity, activity of a free radical scavenger, or the like. However, when excessive production of melanin is caused by a change in external environment like excessive exposure to ultraviolet rays, air pollution, stress, or the like, the pigmentation phenomenon occurs in skin to yield skin melanism, small brown spots, freckles, or the like. Skin melanism is caused by the reaction of skin cells against internal and external factors, and the most representative cause is exposure to ultraviolet rays. Namely, once a skin is exposed to ultraviolet rays, tyrosinase is activated. As the tyrosinase activates tyrosine present in skin tissue to oxidize DOPA (dihydroxyphenylalanine) and dopaquinone to produce melanin in the melanocyte of skin pigment cell, melanocyte. This melanin is transferred to keratinocyte of skin and protects skin from ultraviolet rays by keratinization process. As such, melanin is an ultraviolet protecting agent that is essentially required in human body, and it also plays a role of an effective free radical scavenger for removing various radicals that can cause deformation of biological components like protein, lipid, and nucleic acid. However, if there is locally excessive production of melanin or deterioration of a physiological function of skin which is diminished by aging or skin lesion, melanin is precipitated on a skin surface to yield small brown spots, freckles, and various pigmentations. Since the cause and mechanism of skin melanism are known as described in the above, for producing a skin whitening cosmetics, a method of blending materials having an inhibitory effect on the activity of tyrosinase, which is an enzyme involved with a skin melanism process, or a method of reducing melanin production by inhibiting part of the reactions during melanin production process is generally used. Representative materials used for such purpose include chemical materials such as ascorbic acid, kojic acid, or hydroquinone, and plant extracts such as mulberry root skin extract or liquorice extract. However, ascorbic acid is not suitable as a melanin production inhibitor because it has not only an insufficient inhibitory effect on tyrosinase activity but also poor stability of the molecule itself. Although kojic acid is excellent in inhibitory activity on tyrosinase, there is a problem in terms of the stability like discoloration after blending in cosmetic materials and lower potency according to a change over time, and, due to significant skin irritation, it has a limitation in terms of actual use. Use of hydroquinone as a cosmetic material is also limited due to a problem related to skin irritation and safety. Therefore, there is growing interest in development of a novel and effective skin whitening component.
Meanwhile, in Japanese Patent Application Laid-Open No. 1994-016531, a cosmetic material is disclosed, and in Korean Patent Registration No. 1525090, a cosmetic composition for skin whitening is disclosed. However, there is no disclosure relating to a composition for skin whitening comprising, as an effective ingredient, amorphigeni of the present invention.